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#include <shared/mem.h>
#include <shared/syscalls.h>
#include <stddef.h>
#include <user/lib/malloc.h>
struct node {
const char *name;
size_t namelen;
struct node *next;
char *buf;
size_t size, capacity;
};
struct node *root = NULL;
static struct node special_root;
static struct node *lookup(const char *path, size_t len) {
for (struct node *iter = root; iter; iter = iter->next) {
if (iter->namelen == len && !memcmp(path, iter->name, len))
return iter;
}
return NULL;
}
static struct node *tmpfs_open(const char *path, struct fs_wait_response *res) {
struct node *node;
if (res->len == 0) return NULL;
path++;
res->len--;
if (res->len == 0) return &special_root;
// no directory support (yet)
if (memchr(path, '/', res->len)) return NULL;
node = lookup(path, res->len);
if (!node && (res->flags & OPEN_CREATE)) {
node = malloc(sizeof *node);
memset(node, 0, sizeof *node);
char *namebuf = malloc(res->len);
memcpy(namebuf, path, res->len);
node->name = namebuf;
node->namelen = res->len;
node->next = root;
root = node;
}
return node;
}
void tmpfs_drv(void) {
// TODO replace all the static allocations in drivers with mallocs
static char buf[512];
struct fs_wait_response res;
struct node *ptr;
while (!_syscall_fs_wait(buf, sizeof buf, &res)) {
switch (res.op) {
case VFSOP_OPEN:
ptr = tmpfs_open(buf, &res);
_syscall_fs_respond(ptr, ptr ? 0 : -1, 0);
break;
case VFSOP_READ:
ptr = (void*)res.id;
if (ptr == &special_root) {
size_t buf_pos = 0;
size_t to_skip = res.offset;
for (struct node *iter = root; iter; iter = iter->next) {
if (iter->namelen <= to_skip) {
to_skip -= iter->namelen;
continue;
}
if (iter->namelen + buf_pos - to_skip >= sizeof(buf)) {
memcpy(buf + buf_pos, iter->name + to_skip, sizeof(buf) - buf_pos - to_skip);
buf_pos = sizeof(buf);
break;
}
memcpy(buf + buf_pos, iter->name + to_skip, iter->namelen - to_skip);
buf_pos += iter->namelen - to_skip;
buf[buf_pos++] = '\0';
to_skip = 0;
}
_syscall_fs_respond(buf, buf_pos, 0);
} else {
// TODO offset
if (res.offset)
_syscall_fs_respond(NULL, 0, 0);
else
_syscall_fs_respond(ptr->buf, ptr->size, 0);
break;
}
break;
case VFSOP_WRITE:
ptr = (void*)res.id;
if (ptr == &special_root) {
_syscall_fs_respond(NULL, -1, 0);
break;
}
if (res.len == 0) {
_syscall_fs_respond(NULL, 0, 0);
break;
}
if (!ptr->buf) {
ptr->buf = malloc(256);
if (!ptr->buf) {
_syscall_fs_respond(NULL, -1, 0);
break;
}
memset(ptr->buf, 0, 256);
ptr->capacity = 256;
}
size_t len = res.len;
if (len > ptr->capacity - res.offset)
len = ptr->capacity - res.offset;
memcpy(ptr->buf + res.offset, buf, len);
if (ptr->size < res.offset + len)
ptr->size = res.offset + len;
_syscall_fs_respond(NULL, len, 0);
break;
default:
_syscall_fs_respond(NULL, -1, 0);
break;
}
}
_syscall_exit(1);
}
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